Ask A Laboratory Scientist
This form enables patients to ask specific questions about lab tests. Your questions will be answered by a laboratory scientist as part of a voluntary service provided by one of our partners, American Society for Clinical Laboratory Science. Please allow 2-3 business days for an email response from one of the volunteers on the Consumer Information Response Team.
Looking For Reference Ranges
You may be able to find your test results on your laboratorys website or patient portal. However, you are currently at Testing.com. You may have been directed here by your labs website in order to provide you with background information about the test you had performed. You will need to return to your labs website or portal, or contact your healthcare practitioner in order to obtain your test results.
Testing.com is an award-winning patient education website offering information on laboratory tests. The content on the site, which has been reviewed by laboratory scientists and other medical professionals, provides general explanations of what results might mean for each test listed on the site, such as what a high or low value might suggest to your healthcare practitioner about your health or medical condition.
The reference ranges for your tests can be found on your laboratory report. They are typically found to the right of your results.
If you do not have your lab report, consult your healthcare provider or the laboratory that performed the test to obtain the reference range.
For more information, please read the article Reference Ranges and What They Mean.
What Should I Expect During An Allergy Test
The purpose of skin tests is to see how your body responds to allergens. If you have an allergic reaction, youll develop a reaction at the site of the test. Rarely patients may have mild allergy symptoms such as itchy skin, watery eyes and congestion. Most symptoms clear up in one to two hours after the test, the redness or wheals may remain for several more hours.
Read Also: What To Do If You Have Seasonal Allergies
When Allergy Testing Is Appropriate
Allergy testing is usually performed on people with suspected allergic rhinitis , asthma or reactions to insects or foods. In people with allergic rhinitis or asthma, allergy testing usually includes house dust mite, cat and dog dander , mould spores, pollen from relevant grasses, weeds or trees and in some cases, occupational allergens. Testing can also be used to confirm suspected allergies to foods, stinging insects and some medicines.
It is important to note that:
- Allergy test results cannot be used on their own and must be considered together with your clinical history.
- Medicare rebates are available for skin prick tests or blood tests for allergen specific IgE in Australia.
- In some cases, you may be referred to a clinical immunology/allergy specialist for further detailed assessment.
The Wrong Test Can Be A Waste Of Money
Allergy tests can cost a lot. A skin allergy test can cost $60 to $300. A blood test can cost $200 to $1,000. A blood test for food allergies can cost hundreds of dollars, and testing for chronic hives can cost thousands of dollars. Your health insurance may not cover the costs of these tests. And without a doctors exam, the test may not even tell you what is causing your symptoms or how to treat them.
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Indications For An Allergy Blood Test
The indications for an allergy blood test are allergy symptoms, including the following:
- Runny or stuffy nose
- Shortness of breath
Whether you experience any of the symptoms due to seasonal changes or after exposure to certain foods and beverages, it is best to have your allergy diagnosed and treated as soon as possible. Some people think that mild allergies can be ignored or self-diagnosed, but it is always important to see a doctor, regardless of your allergies. Allergic reactions can change and grow more severe with time, so the sooner you get your problem diagnosed, the better off youll be.
Heres What You Need To Know
The only way to proactively avoid having high IgE levels is to avoid the things that may be causing an allergic reaction. The levels of antibodies in the blood are not affected by the amount of exercise a person performs daily or the foods they choose to eat.
Doctors that specialize in diagnosing allergies will often perform this test within their own offices. General family providers will typically send out the sample for analysis and receive results in 3-5 business days. If the test is positive, then further testing may be required to determine the extent of the allergy.
One of the usual tests outside of the allergen-specific IgE blood tests is the allergen skin test. In this test, the skin is pricked so that it will bleed. Then the suspected allergens are exposed to the blood to determine if an allergy develops. Positive skin test results for allergies will cause a red swelling to occur at the application site. Multiple skin pricks are required for each allergen, so it is not typically a test that is performed unless all other detection methods have been exhausted.
Having uncontrolled allergies may not seem serious, but they can be. A severe allergic reaction may cause swelling in the face and throat, making it difficult to breathe. That type of reaction is always treated as a medical emergency.
Recommended Reading: Why Do Some People Have Allergies
Why Choose An Allergy Blood Test
A blood test may be a better option for people who are not able to stop taking their medications. In some cases, medications will interfere with the accuracy of a skin test therefore, a blood test is the better option. In people with severe skin disorders or if your skin reacts to almost anything, it is very difficult to read a skin test, so a blood test is much easier to read.
The Risks Of Allergy Testing
Allergy tests may result in mild itching, redness, and swelling of the skin. Sometimes, small bumps called wheals appear on the skin.
These symptoms often clear up within hours but may last for a few days. Mild topical steroid creams can alleviate these symptoms.
On rare occasions, allergy tests produce an immediate, severe allergic reaction that requires medical attention. Thats why allergy tests should be conducted in a doctors office that has adequate medications and equipment, including epinephrine to treat anaphylaxis, which is a potentially life threatening acute allergic reaction.
Call 911 immediately if you have symptoms of anaphylaxis, such as:
- swelling of the throat
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Rast Test Vs Skin Test
Different kinds of allergy tests are available, but the most commonly used is a skin or pinprick test.
In a skin test, small amounts of different allergens are placed on an individuals skin, usually with a pinprick. People who are allergic to these substances will develop itchy hives at these sites, while others without allergies will not.
The differences between the skin test and the RAST or ELISA blood tests are as follows:
- Speed of the procedure. Skin tests are faster than blood tests. A skin test can take place in the doctors office, but in a RAST or ELISA test, the medical professional must send a blood sample to a laboratory for testing.
- Speed of results. Reactions to a skin test typically develop within 15 minutes, whereas it can take between a few days and 2 weeks to get the results of a RAST test.
- Accuracy. Skin tests may be more sensitive than blood tests, though both methods are considered accurate for diagnosing allergies. It may be more difficult to interpret accurately skin test results on people with darker skin, and skin tests may be affected by medications while blood tests are not.
- Safety. Although it is rare, a person can develop a serious reaction to an allergen used in a skin test. There is no risk of this with a blood test, such as RAST or ELISA.
- Cost. A skin test costs less than a RAST or ELISA test to process, which may be a consideration for some people.
What Is The Allergy Blood Test Process Like
A blood test conducted at one of our clinics in Atlanta, Canton, Duluth and other Georgia locations is a quick process. A sample of blood will be taken from your arm with little to no pain in most cases. The sample of blood can then be sent to a testing laboratory for analysis. After test results are confirmed, your allergist can inform you of the findings and discuss appropriate treatments. Unlike some other food allergy tests, in preparing for a blood test you usually will not need to stop any medications.
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Blood Tests Vs Skin Tests
Both the blood test and the skin prick tests detect food-specific IgE. With the skin tests, the result is immediate, but the blood test result will take at least several days to arrive. Unlike the skin prick test, the blood test is not affected by antihistamines and can be performed for people with extensive rashes that prevent using skin tests.
Preparing For Your Apt
- APT will require a series of visits to our clinic over a few days.
- About a month before the first appointment, you’ll need to stop taking certain medications, including oral steroids. Your allergist and/or food allergy nurse will go over this with you in detail, so you understand which medications to stop and when to stop them.
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How To Read Blood Test Results
While every laboratory or test-providing company may structure their result reports differently, they all must include the same components as mandated by federal legislation.
Some of that may be administrative content, such as the name of the person who did the blood test, the date the test was done, and the name of the doctor who ordered the test.
When it comes to understanding the results, you can look for the following :
- Quantitative test result. Results will be typically written out numerically in cases when the test measured the quantity of something. For example, if the test measured the amount of cholesterol in your blood.
- Abnormal markers. Often, a laboratory report will include some kind of marker to let you know if a result is outside the normal interval, and therefore abnormal. For example, you may see the letter H to indicate high, the letter L to indicate low, or the acronym WNL for within normal limits. You may see an asterisk and some additional comments in text if your results come out as highly abnormal. In this case, youll typically get a call from your doctor.
- Reference range. Every laboratory will have its own reference range for each type of test. Typically, this reference range will be written in your laboratory report next to the numerical value of your result so you are able to see where your result falls in the range.
To a blood test, the nurse or technician:
So When Should You Have Allergy Tests
If you have allergy symptoms, you may get relief from self-help steps and over-the-counter drugs. If these steps do not help your symptoms, then it is time to see your doctor.
The doctor should ask you about your medical history and make sure you get the right tests. If your medical history suggests that you have an allergy, your doctor might refer you to an allergist or immunologist for testing.
- A skin test is the most common kind of allergy test. Your skin is pricked with a needle that has a tiny amount of something you might be allergic to.
- If you have a rash or take a medicine that could affect the results of a skin test, you may need a blood test.
- For chronic hives, you usually do not need an allergy test. However, your doctor might order tests to make sure that the hives are not caused by other conditions, such as a thyroid disorder.
This report is for you to use when talking with your healthcare provider. It is not a substitute for medical advice and treatment. Use of this report is at your own risk.
07/2012
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Allergy Blood Test Vs Allergy Skin Test: Whats The Difference
Allergy blood tests and allergy skin tests are two of the most common forms of allergy testing. During an allergy skin test, your healthcare provider creates tiny pinpricks in your skin and then applies an allergen to check for a reaction.
Skin tests deliver immediate results, but blood tests take a few days. Skin tests tend to be more accurate, but some people cant have allergy skin tests. If you have a skin condition such as hives or a rash, or youre taking antihistamines, allergy skin tests wont deliver reliable results. In these cases, you may need an allergy blood test.
Blood Tests For Allergy Testing
The blood tests are most commonly used to diagnose allergies if the vet suspects inhalant allergies. There are two blood tests that can be used in canines to detect allergies. The vet will extract a blood sampleand perform the test on the sample. The two tests are the RAST test and the ELISA test. These are both similar in methodology, but the ELISA test is considered superior, giving more accurate results.
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Adding Diagnostic Testing To Aid In A Differential Diagnosis Has Been Shown To Increase Confidence In Diagnosis To 90 Percent910
Help your patients find answers.
When a patientâs symptoms and clinical presentation offer a wide range of diagnostic possibilities, such as an IgE-mediated allergy, test results can be a valuable tool in helping confirm the diagnosis. Together with the case history, serological testing can help bring clarity to an uncertain diagnosis and provide clear results that are easy to interpret and explain to patients.
Take the next step.
From ordering a specific IgE test to interpreting results, we have the resources you need to feel confident in your allergy diagnosis.
What Is Allergy Testing
Healthcare providers perform allergy tests to determine whether your immune system overreacts to certain substances . If you have an allergic reaction, it means you have an allergy.
People can be allergic to things in the environment like mold, pollen and pet dander. Some people have allergic reactions to bee stings or latex. People with food allergies may not be able to tolerate peanuts, milk or soy.
Also Check: How Long Do Eye Allergies Last
How Is It Used
The allergen-specific IgE antibody test is a blood test used to help diagnose an allergy to a specific substance or substances for a person who presents with acute or chronic allergy-like symptoms. This is especially true if symptoms are recurrent and appear to be tied to triggers, such as exposures to particular foods or environments, and if other family members are known to have allergies.
Other types of allergy tests may be performed by exposing a person to different substances under careful medical supervision. The usefulness of these tests, however, can be affected by skin conditions, such as significant dermatitis or eczema, and by medications, such as antihistamines and some antidepressants. With some tests there is also the potential for severe reactions, including, for example, anaphylaxis, which can be life-threatening. In these cases, the allergen-specific IgE antibody test may be ordered as an alternative, as it is performed on a blood sample.
The allergen-specific IgE antibody test may also be performed to monitor immunotherapy or to see if a child has outgrown an allergy. Typically, the health care practitioner will interpret the results of the test in comparison with a persons symptoms and any other allergy tests being performed.
Why Your Child May Need An Allergen
Your childs doctor may order an allergen-specific IgE test if your child has some or all the following symptoms of an allergy:
- Stuffy or runny nose
An allergen-specific IgE blood test may be used in addition to or instead of skin testing. IgE blood tests are often used when children have a skin condition that may interfere with skin testing or cannot stop taking their antihistamines.
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How Allergies Are Diagnosed
Your healthcare provider may suspect allergies based on your symptoms and health history or a physical examination. The test they choose to diagnose allergies often depends on what type of trigger they think may be responsible for your symptoms.
If you have been taking antihistamines for your symptoms, you will likely need to stop taking them for a period of time before you can be skin tested.
How Do Allergy Blood Tests Work
The allergy blood test requires highly specialised precision analytical equipment to measure the amount of allergic antibody circulating in the blood against specific allergens. This level generally relates to the likelihood of allergy in as much as the larger amount of antibodies present, the more likely it is that there is a genuine allergy, but this does need to be interpreted together with the clinical history in order to provide meaningful diagnoses. It is important to recognise that IgE blood testing does not give us useful information about the severity of an allergy and a high number on the test does not equate to a likelihood of a severe reaction. That said, component allergy testing can help differentiate between different types of allergies where there may be a risk of severe reaction with one type but not with another.
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How Do You Prepare For Your Blood Test
No special preparation is required and there is no need to fast or indeed be off antihistamines in the way that you do need to be for a skin prick test. For younger children, numbing cream can be applied to make the process of drawing blood less unpleasant. For the newer protein microarrays, a relatively small amount of blood is required and in the case of the ALEX test, this can sometimes be done at home using a finger prick.
